The invention relates to a cylinder head gasket with a gasket plate having at least two juxtaposed passage opening separated by a web, as well as with metallic, circular reinforcing borders of said passage opening and with a metallic, lamina-like reinforcement located in the web area.
The gasket plates of such cylinder head gaskets are normally made from a soft material, which can be reinforced with a metal carrier. All-metal gasket plates are also known. Under the sealing pressure the gasket plate must deform to such an extent that when fitted in an internal combustion engine the adaptation to the sealing faces necessary for sealing purposes is obtained. The cross-sectionally U-shaped borders bent over the opening rim and which have to ensure the necessary sealing against the high combustion chamber pressures serve to produce a locally increased contact pressure. In addition, said border has the function of shielding the soft material against the hot combustion gases.
The compact construction of modern internal combustion engines leads to limited distances between the passage opening or cylinders and consequently the web widths are small. This leads to the sealing material being located there to a greater extent than in the remaining areas, i.e. the contact pressure drops and there is a risk of a gas exchange between the cylinders. This can lead to a destruction of the gaskets in this area and therefore to an engine failure.
This effect is counteracted by increasing the gasket thickness and the metallic proportion in the thermally endangered web areas by using a lamina-like reinforcement. The metal also brings about a better heat dissipation to the adjacent components. It is a common feature of all known solutions that the reinforcements have a constant thickness and the thickness, position and geometry adapted to the web shapes are dependent on engine-specific factors. At the front ends of the reinforcements there is an abrupt bend corresponding to the thickness thereof and in the fitted state this leads to a sudden pressure drop or in the extreme case to a gap between the sealing faces.
A further disadvantage of the known reinforcements is that, as a result of the predetermined geometry of the sealed engine parts pressed together by means of socket head studs, the cylinder head is supported in preferred manner on the flat reinforcement in the said area and leads to a pressure reduction there.